IBM 6150 Hardware Maintenance Manual page 158

Step 5
Listen to the tape drive.
IS THE NOISE COMING FROM THE TAPE DRIVE?
YES
The tape drive is causing the noise.
1. Exchange the tape drive.
2. Run the System Checkout.
3. This completes the repair.
NO Follow the procedures for servicing the device which has the noise
problem.
(9/86) Problem Isolation Charts 3-0050-5